Method for honing a stator and machine for carrying out the method

ABSTRACT

The invention relates to a method for machining a stator opening of a stator and a bearing opening of an electromechanical converter, in particular an electric motor, the method comprising the steps of honing the stator opening using a honing tool and machining, preferably honing, the bearing opening.

BACKGROUND OF THE INVENTION

The present invention relates to a method for machining a stator opening of a stator and a bearing opening of an electromechanical converter, in particular of an electric motor, wherein the method comprises the steps of honing the stator opening using a honing tool and machining, preferably honing, the bearing opening. The bearing opening serves to receive the rotor (or a rotor shaft on which the rotor is arranged) of the electromechanical converter.

With electromechanical converters, especially electric motors, the gap width between the outer circumference of the rotor and the inner circumference of the stator affects the efficiency of the electromechanical converter. A smaller gap width increases efficiency.

A lower limit for the achievable gap widths results from the need to avoid rubbing against the rotor during operation and to keep the machining effort for the surfaces, in particular the stator, to an economically/technically reasonable level.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a method with which the stator and the bearing opening, which serves to receive the rotor, can be machined in a way that enables the smallest possible gap width between rotor and stator. In addition to a small gap width, coaxial positioning of the rotor and stator with respect to one another should preferably also be achieved in order to ensure a parallel position of the functional surfaces of the rotor and stator.

This object is achieved by a method according to claim 1. The method according to the invention is characterized in that a tool for machining the bearing opening is aligned coaxially with the stator opening via a centering device which engages in the stator opening during the machining of the bearing opening, or in that the honing tool for honing the stator opening is aligned coaxially with the bearing opening via a centering device which engages in the bearing opening. A centering device for the tool for machining the bearing opening is to be understood as a device which, via mechanical engagement in the stator opening, predetermines an alignment of the axis of the machining of the bearing opening. For example, the centering device may comprise a centering mandrel which detects the position of the stator opening and is mechanically coupled to the tool for machining the bearing opening in such a way that it predetermines its axial position. It is also conceivable that the centering device comprises the honing tool that is provided for machining the stator opening. In this case, the honing tool can be coupled to the tool for machining the bearing opening in such a way that both are aligned coaxially with one another and ensure a coaxial course of the stator opening and bearing opening during simultaneous machining of the stator opening and bearing opening.

A centering device for the honing tool for honing the stator opening is to be understood as a device which, via mechanical engagement in the bearing opening, predetermines an alignment of the axis for honing the stator opening. For example, the centering device may comprise a centering mandrel that detects the alignment of the bearing opening and is mechanically coupled to the honing tool for machining the stator opening in such a way that it predetermines its axial position.

It is optionally possible in the sense of the invention that the honing tool for machining the stator opening and the tool for machining the bearing opening is a multi-tiered honing tool. Such a multi-tiered honing tool may comprise a first honing section with a first set of honing stones and a second honing section with a second set of honing stones. The arrangement of the two honing sections on one tool axis always ensures coaxial machining of the stator opening and the bearing opening. When using such a multi-tiered honing tool, the honing section that is used to machine the stator opening represents not only the honing tool for machining the stator opening, but also the centering device in the sense of the present invention.

According to the invention, if a multi-tiered tool is used for the machining of the stator opening and the bearing opening that comprises a first honing section with a first set of honing stones, wherein the first honing section may comprise passive centering bars which can be extended after a honing operation has been completed, wherein the honing stones can be retracted. The centering bars can then act as a centering device and the multi-tiered tool can comprise a second honing section with a second set of honing stones which can be extended after the honing of the stator opening and can hone or machine the bearing opening, while the centering bars ensure the coaxial course of the second honing section for the stator opening.

The stator comprises stacked lamina, between which there is insulation material. During the machining of the inner surface of the stator, burrs can be produced which can contact the adjacent lamina. The function of the stator, however, requires avoiding contacting the individual lamina in order to avoid the formation of eddy currents. There is therefore a need for the lamina edges on the inside of the stator to be largely free of burrs. This is achieved by the honing operation or honing operations described above. This also enables the machining of the individual lamina to a uniform diameter and the removal of paint residues on the curved inner surface of the stator.

Honing the stator opening achieves a high surface quality and roundness of the stator opening; moreover, the method according to the invention ensures that the bearing opening is aligned coaxially with the stator opening and that the rotor can accordingly be aligned coaxially with the stator, so that a minimal gap width between the rotor and the stator can be achieved. As a result, a correspondingly machined electromechanical converter can be efficiently designed.

By minimizing the gap width, the electrical field strength and thus the efficiency of the electromechanical converter increase and the electromechanical converter runs smoothly.

It is optional if the stator is joined to a housing section that comprises the bearing opening during the honing of the stator opening. The stator can thus already be inserted or pressed into the housing during the machining of the stator opening. The honing of the stator opening can be carried out, for example, at the same time as the machining of the bearing opening.

It is optional if the stator is not joined to a housing section that comprises the bearing opening during the honing of the stator opening. The stator can be handled individually and can only be inserted into the housing after the honing has been completed. As a result, the method step of honing the stator can be carried out on a conventional honing machine with a conventional honing awl.

It is optional if the stator opening is honed before the bearing opening is machined, preferably honed. As a result, a conventional honing tool can be used for honing the stator opening.

It is optional if the honing of the stator opening and the machining of the bearing opening take place, preferably with the bearing opening being honed, in particular with the stator opening and the bearing opening taking place simultaneously using a tiered honing tool having two honing sections separated from one another. This can reduce the cycle time during machining. In particular during the simultaneous honing of the bearing opening and the stator opening, the method according to the invention can thereby be carried out in a particularly time-efficient manner.

It is optional if the method—after the honing of the stator opening and the machining of the first bearing opening—comprises a machining, preferably honing, of a second bearing opening, a tool for machining the second bearing opening being aligned coaxially with the stator opening or the first bearing opening via a centering device which engages in the stator opening or the first bearing opening during the machining of the second bearing opening. The stator of the electromechanical converter can then be mounted in two bearing openings, both of which are aligned coaxially with the stator opening. This variant of the method according to the invention can be implemented particularly easily if a honing tool is used which comprises a centering section which is introduced into the first bearing opening and a honing section which is introduced into the second bearing opening. The centering section can be aligned with respect to the first bearing opening via centering strips and is mechanically coupled to the honing section in such a way that the centering section aligns the honing section coaxially with the first bearing opening, so that the second bearing opening is aligned coaxially with the first bearing opening by the honing operation. After completion of the method variant just described, the stator opening and both bearing openings are then aligned coaxially with one another and have a high surface quality and roundness.

It is optional if the machining of the first bearing opening and, where applicable, the second bearing opening comprises at least one of the machining steps among honing, fine boring and reaming. The aforementioned methods allow the position of the bearing opening to be influenced sufficiently to ensure coaxial alignment.

It is optional if the stator opening is honed using honing stones with diamond as the cutting material and/or if the stator opening is honed using honing stones that use a cutting material with a medium grain size (FEPA standard for diamond micro-grain sizes (11.1977, chap. 2.1): “The grain size is defined by measurement parameters from measurements on the enlarged image of the single grain, as seen in the microscope. The grain size is determined by the diameter of the smallest circle that completely surrounds the microscopic image.”), which grain size is smaller than the thickness of the stator lamina and/or, if the stator opening is honed using honing stones that have a cutting agent concentration of at most 20 vol %, in particular 17.5 vol %, in particular 15 vol %, in particular 12.5 vol %. Diamond is particularly suitable as a cutting material for the honing stones during the machining of the stator, since this cutting agent is particularly hard and prevents bridging between the lamina of the stator. The use of a cutting material having an average grain size that is smaller than the thickness of the lamina also counteracts bridging between the lamina of the stator. The aforementioned concentrations of cutting agent ensure that there is always sharp cutting material on the surface of the honing stones, which also has a positive effect on preventing bridging between the lamina of the stator.

It is optional if the stator opening is honed using honing stones with cBN (cubic crystalline boron nitride) as the cutting material. The use of honing stones with conventional cutting materials, such as silicon carbide and/or corundum, is also conceivable.

It is optional if the stator opening is honed with a honing angle of less than 30°. This counteracts bridging between the lamina of the stator. The specified range of honing angles ensures that the cutting movement with a small axial component predominantly runs in the circumferential direction, and, thus, the honing operation takes place predominantly in the direction of the lamina of the stator, so that bridging between the lamina of the stator is effectively prevented. The honing angle is the angle between the vectors of the cutting speed with respectively reversed axial movement. The horizontal line, which corresponds to the course of the stator lamina and corresponds to the direction of the purely rotary movement of the honing tool, represents the bisector of the honing angle. The honing angle is visible on the finished honed components at the resulting honing marks, which run in a cross-cut pattern typical of honing.

Optionally, a centering device is used in the method according to the invention and is designed to be radially adjustable.

Part of the present invention is also a machine tool which is set up and designed to machine the stator opening of a stator and the bearing opening of an electromechanical converter according to any one of the above-described variants of the method according to the invention. In particular, such a machine tool may comprise a tool for machining the bearing opening, which tool comprises a centering device via which the tool for machining the bearing opening can engage in the stator opening during the machining of the bearing opening and can align the tool coaxially with the stator opening.

Optionally, the machine tool has a centering device that is designed to be radially adjustable.

Preferably, the machine tool is characterized in that it comprises a workpiece holder and an assembly device, the workpiece holder being designed to hold a first housing section of a housing of an electromechanical converter comprising a first bearing opening and the assembly device being designed to attach a second housing section of a housing of an electromechanical converter comprising the second bearing opening to the first housing section. “Attach” here is to be understood as meaning that the second housing section is placed on the first housing section in an intended assembly position. The machine tool preferably also includes a joining device which is designed to join the first housing section to the second housing section, for example to weld, glue or screw them into one another.

The machine tool preferably has a rotary table. The rotary table can be designed, for example, to transport the electromechanical converter from one machining station to the next. For example, the tool for machining the first bearing opening and the tool for machining the second bearing opening, and preferably also the honing tool for machining the stator opening, can be arranged at different machining stations of the machine tool. The aforementioned assembly device can be arranged at one of the machining stations at which the honing tool for machining the stator opening or one of the tools for machining the first or the second bearing opening is arranged. However, the assembly device can also be arranged at a separate further machining station.

However, the rotary table can also be designed to bring different tools into a machining position at a machining station than the electromechanical converter. For example, the rotary table can move the honing tool for machining the stator opening and/or one or both of the tools for machining the first or the second bearing opening and/or the assembly device into a machining position relative to the electromechanical converter.

The machine tool may also include a workpiece manipulation device, which is designed to move the housing of the electromechanical converter from a first machining position, in which the first bearing opening is aligned for the machining, into a second machining position, in which the second bearing opening is aligned for machining.

Advantageously, the machine tool may include a workpiece holder, which is designed to hold an electromechanical converter and the electromechanical converter held therein to move, preferably rotate the housing of the electromechanical converter from a first machining position, in which the first bearing opening is aligned for machining, into a second machining position, in which the second bearing opening is aligned for machining. In this case, the workpiece holder more or less forms a workpiece manipulation device.

The machine tool can also be designed such that the tool for machining the first bearing opening is arranged on a different side of the electromechanical converter than the tool for machining the second bearing opening, the the tool for machining the first bearing opening preferably machining the first bearing opening from a different side than the tool for machining the second bearing opening machines the second bearing opening. For example, the tool for machining the first bearing opening can be arranged in the machine tool above the electromechanical converter and machine the first bearing opening from above, and the tool for machining the second bearing opening can be arranged below the electromechanical converter and machine the second bearing opening from below.

Part of the present invention is also an electromechanical converter having a housing in which the stator of the converter is accommodated, the housing comprising at least one bearing opening, preferably two bearing openings, the bearing opening or bearing openings serving to receive a rotor or the rotor shaft of the electromechanical converter, the stator opening and a bearing opening, where applicable two bearing openings, being machined according to any one of the above-described variants of the method according to the invention. Such an electromechanical converter can have a particularly high degree of efficiency since its gap width can be made minimal.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features, possible applications and advantages of the invention result from the following description of exemplary embodiments of the invention, which are explained with reference to the drawing, where the features may be essential for the invention, both on their own and in different combinations, without being explicitly mentioned again. Shown in the drawings are:

FIG. 1 an electromechanical converter in a schematic sectional view;

FIG. 2 a stator in a schematic sectional view,

FIG. 3 a further stator in a perspective view;

FIG. 4 different steps of a method according to the invention;

FIG. 5 different steps of an alternative method according to the invention;

FIG. 6 different steps of an alternative method according to the invention;

FIG. 7 a machining station of a machine tool;

FIG. 8 a further machining station of the machine tool;

FIG. 9 a rotation of the electromechanical converter in the machine tool by means of a workpiece manipulation device of the machine tool;

FIG. 10 a further machining station of the machine tool; and

FIG. 11 the machine tool in a schematic representation.

DETAILED DESCRIPTION

Corresponding components and elements bear the same reference characters in the following figures. For the sake of clarity, not all reference characters are shown in all figures.

FIG. 1 shows a schematic sectional illustration of an electromechanical converter 10. The electromechanical converter 10 comprises a housing 12. The housing 12 comprises a first bearing opening 14 in a first housing section 15 and a second bearing opening 16 in a second housing section 17. A rotor 18 is arranged in the housing 12. The rotor 18 is arranged on a rotor shaft 19. The rotor shaft 19 is received in the bearing openings 14, 16. The rotor shaft 19 comprises a first shaft section 20 and a second shaft section 22, the shaft sections 20, 22 being received in the respective bearing openings 14, 16 and being rotatably mounted.

A stator 24 of the electromechanical converter 10 is arranged around the rotor 18 within the housing 12. In other words, the rotor 18 is arranged in a stator opening 26.

A gap width between the rotor 18 and the stator 24 is exaggerated in its representation here and bears the reference symbol 28.

The stator opening 26 is honed in the present case according to any one of the methods described below. The bearing openings 14, 16 are machined according to any one of the methods described below.

FIG. 2 shows the stator 24 in the perspective of FIG. 1 individually in a sectional view. Individual lamina of the stator 24 each have the reference symbol 30 and are each separated from one another by an insulation layer 32.

The stator opening 26 has a plurality of interruptions 34. An alternative embodiment with more opening interruptions 34 of the stator 24 is shown in FIG. 3, FIG. 3 showing a perspective view of such a stator 24.

FIG. 4 shows an illustration of a method according to the invention.

FIG. 4 a) shows a first step of a method according to the invention.

In this first step, the stator 24 or the stator opening 26 is machined in the present embodiment of the method. In the variant of FIG. 4a ), the stator 24 is not joined to a housing 12. In this case, the stator is not joined to the first housing section 15. Alternatively, the stator 24 can be arranged in the housing 12 or joined to it, in particular pressed into it. In this case, the stator is joined to the first housing section 15. The variant described last is shown in FIG. 4b ). FIGS. 4a ) and 4 b) thus show alternatives of the first step of the method. In this first step, the stator opening 26 is honed using a honing tool 36. The honing tool 36 in the present case has a plurality of honing stones 38.

The stator opening 26 can be honed using honing stones 38 having diamond as the cutting material 40. The honing of the stator opening 26 can also or additionally be carried out using honing stones 38, which have cutting material 40 with an average grain size that is smaller than the thickness of the lamina 30 of the stator 24. The honing of the stator opening 24 can also or additionally be carried out using honing stones 38 which have a cutting agent concentration of at most 20 vol %, in particular 17.5 vol %, in particular 15 vol %, in particular 12.5 vol %.

The honing of the stator opening 24 can also or additionally be carried out with a honing angle of less than 30°.

The honing tool 36 is joined to a honing spindle 42. The joining to the honing spindle 42 is achieved via a joint 44 on the spindle side and a joint 46 on the tool side as well as an articulated rod 48. The articulated joint makes it possible for the honing tool 36 to follow the axial alignment of the stator opening 26 and machine just its surface without significantly affecting the axial position. The articulated rod 48 offers the necessary degrees of freedom for aligning the tool 36 with the stator opening 26 and enables machining on the same axis.

In the method variant shown in FIG. 4, the first bearing opening 14 is machined after the machining or honing of the stator opening 26 has been completed.

In the variant of the method according to the invention shown in FIG. 4, the first bearing opening 14 is also honed. However, other machining operations are also within the meaning of the present invention.

To machine the bearing opening 14, a tool 50, which is designed here as a honing tool 50, has a centering device 52, which in the present case comprises a centering mandrel 54.

During the machining of the first bearing opening 14, the tool 50 for machining the bearing opening 14 is aligned coaxially with the stator opening 26 via the centering device 52 which engages in the stator opening 26. This is illustrated by the common central axis 56 of the stator opening 26 and the bearing opening 14. The tool 50 is more or less aligned coaxially with the stator opening 26 by the centering device 52 in its axial position and machines the bearing opening 14 such that its central axis falls on the central axis of the stator opening 26.

Following the method step from FIG. 4c ), the second bearing opening 16 can optionally be machined in accordance with the method step from FIG. 4d ).

In this case, after the honing of the stator opening 26 and the machining or honing of the first bearing opening 14, the method comprises the machining, preferably honing, of the second bearing opening 16. A tool 58, which is designed here as a honing tool 58, for machining the second bearing opening 16 is aligned coaxially with the first bearing opening 14 during the machining of the second bearing opening 16 via a centering device 60 which engages in the first bearing opening 14. Because of the coaxial alignment with the already machined first bearing opening 14, the tool 58 is also aligned coaxially with the stator opening 26.

The tool 58 is more or less aligned coaxially with the first bearing opening 14 or stator opening 26 by the centering device 60 in its axial position and machines the second bearing opening 16 such that its central axis coincides with the central axis of the stator opening 26 or the first bearing opening 14. The tool 58 is an articulated honing tool 58. This enables machining on the same axis. This means that there is coaxial alignment between the bearing opening 14 and the tool 58 with the centering device 60.

A centering device 60 can advantageously be designed to be radially adjustable in order to enable play-free guiding.

The honing tool 58 for machining the second bearing opening 16 is joined to a honing spindle 62. The joining to the honing spindle 62 is achieved via a joint 64 on the spindle side and a joint 66 on the tool side as well as an articulated rod 68.

In the method variants illustrated in FIG. 4, the tool 50 for machining the first bearing opening 14 is aligned coaxially with the stator opening 26 via the centering device 52, which engages in the stator opening 26 (FIG. 4c ), and the tool 58 for machining the second bearing opening 16 is aligned coaxially with the first bearing opening 14 via the centering device 60, which engages in the first bearing opening 14 (FIG. 4d ). Instead of the variant shown in FIG. 4d ), however, it is also possible to align the tool 58 for the machining of the second bearing opening 16 via the centering device 60 coaxially with the stator opening 26, in which tool the centering device 60 engages in the stator opening 26. In order to do justice to the geometrical relationships illustrated in FIG. 4, the centering device 60 can, for example, be designed with expandability.

5 shows an alternative variant of the method according to the invention. In the variant of FIG. 5 or FIG. 5a ), the honing tool 36 for machining the stator opening 26 is rigidly joined to the tool 50 for machining the first bearing opening 14. The honing tool 36 and the tool 50, which in the present case is also designed as a honing tool, together form a tiered honing tool 51, the honing tool 36 and the tool 50 each forming a honing section of the tiered honing tool 51. In the method step shown in FIG. 5a ), the honing tool 36 for machining the stator opening 26 simultaneously forms a centering device 52 which engages in the stator opening 26 and aligns the tool 50 for machining the first bearing opening 14 coaxially with the stator opening 26. In the method step illustrated in FIG. 5a ), the honing of the stator opening 26 and the machining, in the present case the honing, of the first bearing opening 14 are carried out simultaneously. (In the method shown in FIG. 5a ), the tool 50 can also be seen at the same time as a centering device which engages in the first bearing opening 14 and which aligns the honing tool 36 for machining the stator opening 26 coaxially with the first bearing opening 14).

FIG. 5b ) shows an optional further method step. If the method step shown in FIG. 5 b) is carried out, after the honing of the stator opening 26 and the first bearing opening 14, the method comprises the machining, preferably honing, of the second bearing opening 16. The tool 58, which is designed here as a honing tool 58, for machining the second bearing opening 16 is aligned coaxially with the first bearing opening 14 during the machining of the second bearing opening 16 via the centering device 60, which engages in the first bearing opening 14. Because of the coaxial alignment with the already machined first bearing opening 14, the tool 58 is also aligned coaxially with the stator opening 26.

The tool 58 is more or less aligned coaxially with the first bearing opening 14 or stator opening 26 by the centering device 60 in its axial position and machines the second bearing opening 16 such that its central axis coincides with the central axis of the stator opening 26 or the first bearing opening 14. The tool 58 is articulated. The honing tool 58 for machining the second bearing opening 16 is joined to a honing spindle 62. The joining to the honing spindle 62 is achieved via a joint 64 on the spindle side and a joint 66 on the tool side as well as an articulated rod 68.

FIG. 6 shows an alternative variant of the method according to the invention. In the variant of FIG. 6, the first bearing opening 14 is first machined, in the present case honed.

In a next step, which is shown in FIG. 5b ), the stator opening 26 is honed. The honing tool 36 for machining the stator opening 26 is rigidly joined to a centering device 72 in this variant of the method. The centering device 72 comprises a plurality of centering strips 74 which engage in the already machined first bearing opening 14 and align the honing tool 36 coaxially with the first bearing opening 14.

FIG. 6c ) shows an optional further method step which corresponds to the method step of FIG. 5b ).

Various machining stations of a machine tool 75 according to the invention are shown in FIGS. 7-10. The machine tool 75 itself is shown schematically in FIG. 11, the machine tool 75 being designed and set up to carry out the method according to the invention. The machine tool 75 comprises a machine base 84 and an upper machine section 86. A rotary table 88 is arranged on the machine base 84 as a machine-internal transfer system. The rotary table 88 comprises a plurality of workpiece receptacles 76, which are arranged centrally around an axis of rotation of the rotary table 88. The rotary table 88 moves the electromechanical converter 10 held in the workpiece holder 76 from one machining station to the next via a rotary movement.

In general, the machine tool 75 can have a rotary table 88 as a machine-internal transfer system or be designed as a linear transfer machine. For example, the electromechanical converters 10 can be moved through the machine tool 75 via a linear conveyor belt. A robot-assisted, machine-internal transfer system is also conceivable. It is also conceivable for the workpieces to be moved manually through the machine tool 75.

During the machining of an electromechanical converter 10, it is held in one of the workpiece holders 76 and thereby fixed, preferably mechanically clamped. The machine tool 75 is shown here set up in a machining station in FIG. 7 for carrying out a simultaneous machining of the stator opening 26 and the first bearing opening 15 in accordance with the method illustrated in FIG. 5. For this purpose, the machine tool comprises the tiered honing tool 51. However, the machine tool can also be designed with a honing tool 36 for honing the stator opening 26 and with a tool 50 separate therefrom for machining the bearing opening 14. These two tools are then preferably arranged in different machining stations. However, they can also be arranged in a single machining station and can be positioned, for example, via a tool changer in a machining position relative to the electromechanical converter 10.

A further machining station of the machine tool is shown in FIG. 8. An assembly device 78 is arranged in this machining station. In the present case, the assembly device 78 can be moved flexibly via an articulated arm 80. In the illustration in FIG. 8, the assembly device 78 attaches the second housing section 17 of the housing 12 having the second bearing opening 16 to the first housing section 15. Following the attachment of the second housing section 17, the latter is joined to the first housing section 15. This joining can be done frictionally, positively and/or integrally, for example by gluing, welding, soldering, clamping, riveting and/or screwing.

In order to move the housing 12 or the electromechanical converter 10 from one machining station to the next, the machine tool 75 has the rotary table 88. Other transfer systems are conceivable. For example, the tool 50 for machining the first bearing opening 14, the tool 58 for machining the second bearing opening 16 and the honing tool 36 for machining stator opening 26 can be arranged at different machining stations of the machine tool 75. The assembly device 78 can be arranged at a separate machining station.

However, the rotary table 88 can also be designed to bring different tools into a machining position at a machining station than the electromechanical converter 10. The electromechanical converter 10 is then advantageously arranged immovably in the workpiece holder 76. The rotary table 88 is then advantageously arranged on the machine upper section 86 and rotates the tools relative to the electromechanical converter 10.

The machine tool 75 may also comprise a workpiece manipulation device 90, which is designed to move, preferably rotate, the housing 12 of the electromechanical converter 10 from a first machining position (FIGS. 7 and 8), in which the first bearing opening 14 is aligned for machining, into a second machining position (FIG. 10), in which the second bearing opening 16 is aligned for machining. The workpiece manipulation device 90 is preferably designed in order to be able to rotate the electromechanical converter 10 by 180°. Such a movement, or in the present case rotation, is illustrated in FIG. 9.

A further machining station of the machine tool is shown in FIG. 10. In this machining station, the tool 58 for machining the second bearing opening 16 machines the bearing opening 16.

The workpiece manipulation device 90 can be provided at a dedicated machining station or, as shown in FIG. 11, centrally, so that it can move the electromechanical converter from one machining position to the other in at least one, preferably all, of the machining stations of the machine tool 75. 

1. A method for machining a stator opening of a stator and a bearing opening of an electromechanical converter, the method comprising the steps of honing the stator opening using a honing tool and machining the bearing opening, characterized in that a tool for machining the bearing opening is aligned coaxially with the stator opening during the machining of the bearing opening via a centering device which engages in the stator opening, or in that the honing tool for honing the stator opening is aligned coaxially with the bearing opening via a centering device which engages in the bearing opening.
 2. The method according to claim 1, characterized in that the stator is joined to a housing section which comprises the bearing opening during the honing of the stator opening.
 3. The method according to claim 1, characterized in that the stator is not joined to a housing section which comprises the bearing opening during the honing of the stator opening.
 4. The method according to claim 1, characterized in that the stator opening is honed before the bearing opening is machined.
 5. The method according to claim 1, characterized in that the honing of the stator opening and the machining of the bearing opening take place simultaneously.
 6. The method according to claim 1, characterized in that the method after the honing of the first bearing opening, the stator opening comprises the attachment of a second housing section having a second bearing opening to the first housing section, which comprises the first bearing opening.
 7. The method according to claim 1, characterized in that the method after the honing of the stator opening and the machining of the first bearing opening comprises the machining of the second bearing opening, a tool for machining the second bearing opening being aligned coaxially with the stator opening or the first bearing opening via a centering device which engages in the stator opening or the first bearing opening during the machining of the second bearing opening.
 8. The method according to claim 1, characterized in that the machining of the first bearing opening and, where applicable, the second bearing opening comprises at least one of the machining steps among honing, fine boring and reaming.
 9. The method according to claim 1, characterized in that the stator opening is honed using honing stones with diamond as the cutting material and/or that the stator opening is honed using honing stones that have a cutting material with an average grain size that is smaller than the thickness of the lamina of the stator, and that the stator opening is honed using honing stones which have a cutting agent concentration of at most 20 vol %.
 10. The method according to claim 1, characterized in that the stator opening is honed with a honing angle of less than 30°.
 11. The method according to claim 1, characterized in that a centering device is used that is designed to be radially adjustable. 12-15. (canceled) 